No one can really tell you what exact values you need for a particular overclock. There are too many differences in setup, hardware, and even two 920's are different from one another. You're just gonna have to set you own numbers and test for stability along the way.
ok thanks, I've seen some after reading your post but there are some things that I'm not sure about
What is the safest CPU temp speed?
and if I overclock my CPU to lets say 3.80 GHZ what would be the best voltage
Do I have to lower the memory speed to its default?
4Ghz is a good speed to be at without using much voltage / high temps
I wouldnt go higher then 1.4v max for cpu voltage
Raise the BLK has high as you can before it becomes unstable, then move it two steps down and that can be the highest stable speed.
Typically, if you set your memory on auto it will adjust the dividers properly and you dont have to worry about it.